Synthesis and structure determination of Ce6Cd23Te: a new chalcogen-containing member of theRE6Cd23T family (REis a rare-earth metal and T is a late group 14, 15 and 16 element)

2017 ◽  
Vol 73 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Griffen Desroches ◽  
Svilen Bobev

The ternary phase hexacerium tricosacadmium telluride, Ce6Cd23Te, was synthesized by a high-temperature reaction of the elements in sealed Nb ampoules and was structurally characterized by powder and single-crystal X-ray diffraction. The structure, established from single-crystal X-ray diffraction methods, is isopointal with the Zr6Zn23Si structure type (Pearson symbolcF120, cubic space groupFm-3m), a filled version of the Th6Mn23structure with the same space group and Pearson symbolcF116. Though no Cd-containing rare-earth metal binaries are known to form with this structure, it appears that the addition of small amounts of ap-block element allows the formation of such interstitially stabilized ternary compounds. Temperature-dependent direct current (dc) magnetization measurements suggest local-moment magnetism arising from the Ce3+ground state, with possible valence fluctuations at low temperature, inferred from the deviations from the Curie–Weiss law.

2018 ◽  
Vol 73 (11) ◽  
pp. 927-942 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka

AbstractThe rare earth metal-rich cobalt and nickel aluminium compounds with the general compositions RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu) have been synthesised from the elements by arc-melting, followed by annealing. Single-crystal X-ray diffraction experiments on Y6Co2.02(1)Al0.98(1) (Ho6Co2Ga type; Immm; a=944.1(2), b=952.4(2), c=999.0(2) pm; wR2=0.0452, 1123 F2 values, 35 variables) and Y6Ni2.26(1)Al0.74(1) (Ho6Co2Ga type; Immm; a=938.30(5), b=959.45(5), c=996.05(6) pm; wR2=0.0499, 1131 F2 values, 35 variables) revealed that the compounds form solid solutions according to the general formula RE6(Co/Ni)2+xAl1−x with different homogeneity ranges. The compounds of the Ni series can be obtained in X-ray pure form only with the nominal composition RE6Ni2.25Al0.75. A significant increase of the U22 component of the anisotropic displacement parameters of the Co/Ni2 atoms (4g site) was observed that requires a description of the structure with a split-position model at RT. Further investigations by low temperature (90 K) single-crystal X-ray diffraction experiments of Y6Co2.02(1)Al0.98(1) showed a significant decrease of U22. Magnetic measurements were conducted on the X-ray pure members of the RE6Co2Al (RE=Y, Dy–Tm, Lu) series. Antiferromagnetic ordering was observed for the members with unpaired f electrons with Néel temperatures up to TN=48.0(1) K and two spin reorientations for Dy6Co2Al.


2015 ◽  
Vol 71 (10) ◽  
pp. 894-899 ◽  
Author(s):  
Jai Prakash ◽  
Marion C. Schäfer ◽  
Svilen Bobev

Zintl phases are renowned for their diverse crystal structures with rich structural chemistry and have recently exhibited some remarkable heat- and charge-transport properties. The ternary bismuthidesRELi3Bi2(RE= La–Nd, Sm, Gd, and Tb) (namely, lanthanum trilithium dibismuthide, LaLi3Bi2, cerium trilithium dibismuthide, CeLi3Bi2, praseodymium trilithium dibismuthide, PrLi3Bi2, neodymium trilithium dibismuthide, NdLi3Bi2, samarium trilithium dibismuthide, SmLi3Bi2, gadolinium trilithium dibismuthide, GdLi3Bi2, and terbium trilithium dibismuthide, TbLi3Bi2) were synthesized by high-temperature reactions of the elements in sealed Nb ampoules. Single-crystal X-ray diffraction analysis shows that all seven compounds are isostructural and crystallize in the LaLi3Sb2type structure in the trigonal space groupP\overline{3}m1 (Pearson symbolhP6). The unit-cell volumes decrease monotonically on moving from the La to the Tb compound, owing to the lanthanide contraction. The structure features a rare-earth metal atom and one Li atom in a nearly perfect octahedral coordination by six Bi atoms. The second crystallographically unique Li atom is surrounded by four Bi atoms in a slightly distorted tetrahedral geometry. The atomic arrangements are best described as layered structures consisting of two-dimensional layers of fused LiBi4tetrahedra and LiBi6octahedra, separated by rare-earth metal cations. As such, these compounds are expected to be valance-precise semiconductors, whose formulae can be represented as (RE3+)(Li1+)3(Bi3−)2.


1989 ◽  
Vol 151 ◽  
Author(s):  
W. R. Bennett ◽  
R. F. C. Farrow ◽  
S. S. P. Parkin ◽  
E. E. Marinero

ABSTRACTWe report on the new epitaxial system LaF3/Er/Dy/Er/LaF3/GaAs (111) grown by molecular beam epitaxy. X-ray diffraction studies have been used to determine the epitaxial relationships between the rare earths, the LaF3 and the substrate. Further studies of symmetric and asymmetric reflections yielded the in-plane and perpendicular strain components of the rare earth layers. Such systems may be used to probe the effects of magnetoelastic interactions and dimensionality on magnetic ordering in rare earth metal films and multilayers.


2020 ◽  
Vol 86 (5) ◽  
pp. 3-12
Author(s):  
Bohdana Belan ◽  
Mykola Manyako ◽  
Mariya Dzevenko ◽  
Dorota Kowalska ◽  
Roman Gladyshevskii

The new ternary silicide Lu3Ni11.74(2)Si4 was synthesized from the elements by arc-melting and its crystal structure was determined by the single-crystal X-ray diffraction. The compound crystallizes in the Sc3Ni11Ge4-type: Pearson symbol hP37.2, space group P63/mmc (No. 194), a = 8.0985(16), c = 8.550(2) Å, Z = 2; R = 0.0244, wR = 0.0430 for 244 reflections. The silicide Lu3Ni11.74(2)Si4 is new member of the EuMg5.2-type structure family.


2005 ◽  
Vol 60 (3) ◽  
pp. 265-270 ◽  
Author(s):  
Rainer Kraft ◽  
Rainer Pöttgen

The rare earth metal (RE)-magnesium-thallides REMgTl (RE = Y, La-Nd, Sm, Gd-Tm, Lu) were prepared from the elements in sealed tantalum tubes in a water-cooled sample chamber of a high-frequency furnace. The thallides were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P62m, with three formula units per cell. Four structures were refined from X-ray single crystal diffractometer data: α = 750.5(1), c = 459.85(8) pm, wR2 = 0.0491, 364 F2 values, 14 variables for YMgTl; α = 781.3(1), c = 477.84(8) pm, wR2 = 0.0640, BASF = 0.09(2), 425 F2 values, 15 variables for LaMgTl; α = 774.1(1), c = 473.75(7) pm, wR2 = 0.0405, 295 F2 values, 14 variables for CeMgTl; a = 760.3(1), c = 465.93(8) pm, wR2 = 0.0262, 287 F2 values, 14 variables for SmMgTl. The PrMgTl, NdMgTl, GdMgTl, TbMgTl, and DyMgTl structures have been analyzed using the Rietveld technique. The REMgTl structures contain two cystallographically independent thallium sites, both with tri-capped trigonal prismatic coordination: Tl1Mg3RE6 and Tl2Mg6RE3. Together the magnesium and thallium atoms form three-dimensional [MgTl] networks with Mg-Mg distances of 327 and Mg-Tl distances in the range 299 - 303 pm (data for CeMgTl)


2011 ◽  
Vol 236-238 ◽  
pp. 3041-3045 ◽  
Author(s):  
Ling Mei Yang ◽  
Peng Mei Lv ◽  
Zhen Hong Yuan ◽  
Wen Luo ◽  
Zhong Ming Wang ◽  
...  

Fe(II)-Zn-based double metal cyanide complex catalysts modified with rare earth metal or transition metal promoters(lanthanum, cerium, zirconium, manganese) for the production of biodiesel were prepared, and the effect of the addition of different metal promoters on the characteristics of the catalyst was studied by using X-ray diffraction (XRD), BET, ICP and Infrared techniques .The experiment results show that the Fe(II)-Zn-based catalyst promoted with 1 wt.% of La(NO3)3·nH2O exhibits the highest catalytic activity for the reaction, being as high as 99.3% of the yield of fatty acid methyl esters (FAME). Fe(II)-Zn-based catalysts have a tentative molecular formula: K2Zn3[Fe(CN)6]2·xH2O· (t-BuOH), where x=3-9 determined by using elemental analysis and ICP. It has been shown that the molecular formula of Fe(II)-Zn-based double metal cyanide complex catalysts did not change by adding 1 wt.% of rare earth metal or transition metal promoters. X-ray diffraction and BET results showed that Fe(II)-Zn-based catalysts with 1 wt.% of metal promoters salts exhibit smaller particle size, higher surface area than the Fe(II)-Zn catalyst ,which may be related to the higher activity of the catalysts.


2018 ◽  
Vol 233 (9-10) ◽  
pp. 607-613 ◽  
Author(s):  
Sebastian Stein ◽  
Rainer Pöttgen

Abstract Six new rare earth metal-rich intermetallic compounds RE9CoMg4 with RE=Y, Dy, Ho, Er, Tm and Lu were synthesized by induction-melting the elements in sealed niobium ampoules followed by annealing in muffle furnaces. The structures of Y9CoMg4 and Tm8.56CoMg4.44 were refined from single-crystal X-ray diffraction data: P63/mmc, a=965.65(6), c=971.07(5) pm, wR2=0.0599, 614 F2 values, 20 variables for Y9CoMg4 and a=945.20(4), c=953.11(5) pm, wR2=0.0358, 585 F2 values, 21 variables for Tm8.56CoMg4.44 (a small homogeneity range results from Tm/Mg mixing). The RE9CoMg4 phases crystallize with a coloring variant of the aristotype Co2Al5. The striking structural motif is a hexagonal rod packing of rows of corner- and face-sharing tetrahedral Mg4 clusters with Mg–Mg distances ranging from 304 to 317 pm in Y9CoMg4. These rows are similar to the hexagonal Laves phases REMg2. The space between the rows is filled with rows of face-sharing Co@Y6 trigonal prisms (TP) and empty Y6 octahedra (O) in the sequence –TP–O–O–. The many isopointal coloring variants of the aristotype Co2Al5 are briefly discussed.


2002 ◽  
Vol 12 (9) ◽  
pp. 347-350
Author(s):  
S. van Smaalen ◽  
P. Daniels ◽  
F. Galli ◽  
R. Feyerherm ◽  
E. Dudzik ◽  
...  

X-ray diffraction with synchrotron radiation has been used to study the phase transitions in compounds M5Ir4Si10 with M a rare-earth metal. For M = Er, Ho and Er0.84Lu0.16 phase transitions have been found towards a combined commensurate/incommensurate state, that locks into a commensurate state at lower temperatures. For M = Lu and Er0.66Lu0.34 there is a single transition towards a commensurate state. The results are interpreted in terms of commensurate structural transitions that induce incommensurate CDWs.


1994 ◽  
Vol 49 (11) ◽  
pp. 1525-1530 ◽  
Author(s):  
Rainer Pöttgen

The new ternary stannides RE2Au2Sn (RE = Gd, Tb) and indides RE2Au2In (RE = Y, Gd-Tm, Lu) were synthesized by arc-melting of the elemental components and subsequent annealing at 800 °C. While Gd2Au2Sn, Tb2Au2Sn and the indides with RE = Y, Gd-Er crystallize in the ordered U3Si2 structure, Tm2Au2In and Lu2Au2In adopt the ordered Zr3Al2 structure, respectively. The crystal structure of Dy2Au2In was refined from single-crystal X- ray data: P4/mbm, Z = 2, a = 784.1(1) pm, c = 373.9(1) pm, V = 0.2299 nm3 and R = 0.028 for 342 F2 values and 12 variables. The tin (indium) atoms in these compounds occupy [RE8] square prisms and the gold atoms are surrounded by [RE6] trigonal prisms. These fragments are derived from the AlB2 and CsCl-type structures. The crystal chemistry of these com­pounds is briefly discussed.


2019 ◽  
Vol 48 (17) ◽  
pp. 5614-5620
Author(s):  
Joshua Greenough ◽  
Zheng Zhou ◽  
Zheng Wei ◽  
Marina A. Petrukhina

Two new organometallic cyclooctatetraenyl complexes of the type [M2(COT)3(THF)2] (M = Y and La) have been prepared, using optimized synthetic procedures, and fully characterized by X-ray diffraction analysis, IR and 1H NMR spectroscopies.


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